High-entropy oxide synthesis in concentrated alkaline solutions for plasma-catalytic formaldehyde oxidation

High-concentration NaOH co-precipitation makes high-entropy oxides with high surface area of 173 m 2 g −1 . Tests show that HEO-10%-400 boosts formaldehyde removal by 59.7%, reduces O 3 by 93.1%, and NO x by 91.8% over plasma alone.